Anti-glare/antireflection member and method for producing same

ABSTRACT

Provided is an anti-glare/antireflection member having excellent visibility. The anti-glare/antireflection member ( 1 ) includes a base material ( 10 ) and an antireflection layer ( 20 ). The base material ( 10 ) is provided in a surface layer thereof with an anti-glare layer ( 10   a ) having a concavo-convex configuration. The antireflection layer ( 20 ) is provided on the anti-glare layer ( 10   a ).

TECHNICAL FIELD

The present invention relates to anti-glare/antireflection members andmethods for producing the same.

BACKGROUND ART

From the viewpoint of increasing the visibility of a display, there hasconventionally been proposed the provision of an antireflection layer oran anti-glare layer on a display surface of the display. For example,Patent Literature 1 describes that an antireflection layer formed of alow-refractive index layer is provided on a base material and thesurface of the low-refractive index layer is subjected to an anti-glaretreatment to give the antireflection layer both of an antireflectionfunction and an anti-glare function.

CITATION LIST Patent Literature

-   Patent Literature 1: JP-A-H10-221506

SUMMARY OF INVENTION Technical Problem

There is a demand to further increase the visibility of displays.

A principal object of the present invention is to provide ananti-glare/antireflection member having excellent visibility.

Solution to Problem

An anti-glare/antireflection member according to the present inventionincludes a base material and an antireflection layer. The base materialis provided in a surface layer thereof with an anti-glare layer having aconcavo-convex configuration. The antireflection layer is provided onthe anti-glare layer.

The base material may include a base material body and an island layerdisposed on the base material body and forming the anti-glare layer.

The base material body may be formed of a resin film, a glass film, aresin plate or a glass plate.

The anti-glare/antireflection member according to the present inventionpreferably further includes, on a surface of the base material oppositeto the antireflection layer, another antireflection layer.

The antireflection layer may be formed of a low-refractive index layerhaving a lower refractive index than the base material.

The antireflection layer may be formed of a structure in whichlow-refractive index layers having a relatively low refractive index andhigh-refractive index layers having a relatively high refractive indexare alternately deposited.

The anti-glare/antireflection member may further include an antifoulinglayer containing fluorine and provided on the antireflection layer.

A first method for producing an anti-glare/antireflection memberaccording to the present invention pertains to a method for producingthe aforementioned anti-glare/antireflection member. Alight-transmissive material is applied on a surface of alight-transmissive plate by spraying to form an island layer thereon,thus preparing the base material composed of the light-transmissiveplate and the island layer.

A second method for producing an anti-glare/antireflection memberaccording to the present invention pertains to a method for producingthe aforementioned anti-glare/antireflection member. A surface of alight-transmissive plate is blasted to form the concavo-convexconfiguration, thus preparing the base material.

In the second method for producing an anti-glare/antireflection memberaccording to the present invention, the surface of thelight-transmissive plate is preferably etched after being blasted.

Advantageous Effects of Invention

In the present invention, an anti-glare/antireflection member havingexcellent visibility can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view of ananti-glare/antireflection member according to an embodiment of thepresent invention.

FIG. 2 is a schematic cross-sectional view of ananti-glare/antireflection member according to another embodiment of thepresent invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a description will be given of examples of preferredembodiments for working of the present invention. However, the followingembodiments are simply illustrative. The present invention is not at alllimited to the following embodiments.

Throughout the drawings to which the embodiments and the like refer,elements having substantially the same functions will be referred to bythe same reference signs. The drawings to which the embodiments and thelike refer are schematically illustrated, and the dimensional ratios andthe like of objects illustrated in the drawings may be different fromthose of the actual objects. Different drawings may have differentdimensional ratios and the like of the objects. Dimensional ratios andthe like of specific objects should be determined in consideration ofthe following descriptions.

FIG. 1 is a schematic cross-sectional view of ananti-glare/antireflection member according to this embodiment. Theanti-glare/antireflection member 1 shown in FIG. 1 is a member disposed,for example, on a display surface of a display and used to improve thevisibility of the display. The anti-glare/antireflection member 1 may bea film-like member attached on the display surface of the display or maybe a member forming a front sheet of the display. In other words, theanti-glare/antireflection member 1 may be a member attached to thedisplay afterward or may be a component of the display.

The anti-glare/antireflection member 1 includes a base material 10. Thebase material 10 is provided in a surface layer thereof with ananti-glare layer 10 a having a concavo-convex configuration and ananti-glare function. Specifically, in this embodiment, the base material10 includes a base material body 11 and an island layer 12.

No particular limitation is placed on the constituent material for thebase material body 11 so long as it is a material having lightpermeability. The base material body 11 can be formed of, for example, aresin film, a glass film, a resin plate or a glass plate. The glassplate can be made of, for example, an alkali-free glass substrate, asoda-lime glass substrate, a chemically tempered glass substrate or thelike.

The base material body 11 has a first principal surface 11 a orientedtoward the display in a service condition of theanti-glare/antireflection member 1 and a second principal surface 11 boriented toward the observer in the same condition. In this embodiment,the first and second principal surfaces 11 a, 11 b are formed in a flatsurface.

An island layer 12 is provided on the second principal surface 11 b.This island layer 12 constitutes the anti-glare layer 10 a. The islandlayer 12 is a layer provided in islands. The provision of the islandlayer 12 covering part of the second principal surface 11 b in thismanner results in the formation of a concavo-convex configuration. Theconcavo-convex configuration is preferably free from regularity. Thereason for this is that the anti-glare function of the anti-glare layer10 a increases.

No particular limitation is placed on the constituent material for theisland layer 12 so long as it has light permeability and can adhere tothe base material body 11. The island layer 12 can be made of, forexample, SiO₂, TiO₂, Al₂O₃, ZrO₂ or so on.

An antireflection layer 20 is provided on the anti-glare layer 10 a.Therefore, the antireflection layer 20 is provided on the concavo-convexconfiguration.

The antireflection layer 20 is a layer having the function of reducingthe surface reflectance. The antireflection layer 20 need only be alayer giving a lower surface reflectance when provided than when notprovided and may not necessarily be a layer reducing the surfacereflectance to zero.

The antireflection layer 20 may be formed of, for example, alow-refractive index layer having a lower refractive index than the basematerial 10. Alternatively, the antireflection layer 20 may be formed ofa dielectric multilayer film in which low-refractive index layers havinga relatively low refractive index and high-refractive index layershaving a relatively high refractive index are alternately deposited.

The anti-reflection function of an antireflection layer significantlydepends on the thickness of the antireflection layer. For this reason,the anti-reflection function is generally provided on a flat surface.Therefore, it is conventionally considered that, for example, inproviding both an anti-glare layer and an antireflection layer, theantireflection layer needs to be first formed on a flat surface of abasematerial and the anti-glare layer needs to be then formed on theantireflection layer.

However, the inventors conducted intensive studies and found that byproviding the antireflection layer 20 on the anti-glare layer 10 ahaving a concavo-convex configuration, the visibility of the displaycould be further improved. In other words, the inventors found that evenif the antireflection layer 20 was disposed on the anti-glare layer 10a, a sufficient anti-reflection function could be attained.

The anti-glare/antireflection member 1 can achieve excellent anti-glareproperties since it is provided with the anti-glare layer 10 a.Furthermore, since the antireflection layer 20 is disposed on theanti-glare layer 10 a, the reflectance at the anti-glare layer 10 a isreduced. Thus, the amount of light diffusely reflected by the anti-glarelayer 10 a can be reduced. Therefore, more excellent anti-glareproperties can be achieved.

In addition, since the antireflection layer 20 is provided on theoutermost layer toward the observer, the reflection of the backgroundcan be reduced.

As just described, the use of the anti-glare/antireflection member 1 canprovide excellent anti-glare properties while reducing the reflection ofthe background. Therefore, with the use of the anti-glare/antireflectionmember 1, the visibility of the display can be increased.

An additional layer having a thickness not impairing the function of theantireflection layer 20 may be formed on the antireflection layer 20.For example, as shown in FIG. 2, an antifouling layer 30 of 200 nm orless thickness containing fluorine may be formed on the antireflectionlayer 20. The fluorine-containing antifouling layer 30 may be made of,for example, a polymer having —Si—O—Si— bonds (siloxane bonds) andfluorine-containing, water-repellent functional groups. In thefluorine-containing antifouling layer, the siloxane bonds aresynthesized by dehydrocondensation of dimeric silanol.

In the anti-glare/antireflection member 1, a pressure-sensitive adhesivelayer or an adhesive layer may be provided on the first principalsurface 11 a. Thus, the anti-glare/antireflection member 1 can bepressure-sensitively attached or glued via the pressure-sensitiveadhesive layer or the adhesive layer to the screen of a display, such asa liquid crystal display.

The anti-glare/antireflection member 1 can be produced, for example, inthe following manner. First, a light-transmissive material is applied,by spraying, on a base material body 11 which is a light-transmissiveplate made of, for example, glass or resin and then dried to form anisland layer 12 thereon, thus preparing a base material 10. Thereafter,an antireflection layer 20 is formed on the island layer 12 of the basematerial 10, so that an anti-glare/antireflection member 1 can beproduced. The antireflection layer 20 can be formed by, for example,sputtering, CVD (chemical vapor deposition) or so on.

Alternatively, the base material 10 can be prepared, for example, byblasting a surface of the light-transmissive plate to form aconcavo-convex configuration. In this case, the surface is preferablyetched after being blasted. For example, if the base material is formedof a thin glass plate or a glass film, the base material may be damagedby blasting and, therefore, the anti-glare layer 10 a is preferablyformed by spraying.

The present invention will be described below in more detail withreference to specific examples but the present invention is not at alllimited by the following examples. Modification and variations may beappropriately made therein without changing the gist of the presentinvention.

Example 1

An anti-glare layer made of SiO₂ and having a concavo-convexconfiguration was formed, by spraying, on a substrate of alkali-freeglass OA-10G manufactured by Nippon Electric Glass Co., Ltd. with athickness of 0.5 mm and a surface roughness (Ra) of approximately 0.2nm. The average thickness of the anti-glare layer was approximately 500nm. The haze value of the anti-glare layer was approximately 12.

Next, SiO₂ layers and Nb₂O₅ layers were alternately formed, bysputtering, on the anti-glare layer to give a total of five layers.Thus, an antireflection layer composed of alternately deposited SiO₂ andNb₂O₅ layers was provided on the anti-glare layer. In the above manner,an anti-glare/antireflection member was produced.

The resultant anti-glare/antireflection member was evaluated in terms ofthe reflection of the surroundings and contrast in the followingmanners. The evaluation results are shown in Table 1.

In terms of the reflection of the surroundings, theanti-glare/antireflection member was visually checked at 60° to theperpendicular. If the reflection of the surroundings was notsubstantially identified, this was evaluated as a “⊚”. If the reflectionof the surroundings was identified a little, this was evaluated as a“◯”. If the reflection of the surroundings was identified, this wasevaluated as a “Δ”. If the reflection of the surroundings was clearlyidentified, this was evaluated as a “X”.

The evaluation for contrast was carried out by placing theanti-glare/antireflection member on a liquid crystal screen andobserving an image on the liquid crystal screen through theanti-glare/antireflection member. Specifically, if the image was seenmore clearly than when observing it directly on the liquid crystalscreen, this was evaluated as a “⊚”. If the image was seen as clearly aswhen observing it directly on the liquid crystal screen, this wasevaluated as a “◯”. If the image was seen more blurred than whenobserving it directly on the liquid crystal screen, this was evaluatedas a “X”.

Comparative Example 1

Only an anti-glare layer was formed on a substrate in the same manner asin Example 1 but no antireflection layer was provided. The resultantmember was evaluated in terms of the reflection of the surroundings andcontrast in the same manner as in Example 1. The evaluation results areshown in Table 1.

Comparative Example 2

Only an antireflection layer was formed on a substrate in the samemanner as in Example 1 but no anti-glare layer was provided. Theresultant member was evaluated in terms of the reflection of thesurroundings and contrast in the same manner as in Example 1. Theevaluation results are shown in Table 1.

TABLE 1 Ex. 1 Comp. Ex. 1 Comp. Ex. 2 Contrast ◯ X ⊚ Reflection ⊚ ◯ Δ

As is obvious from the results shown in Table 1, Example 1 wassubstantially free from reflection of the surroundings and had goodcontrast. In Comparative Example 1, the reflection of the surroundingswas identified a little but the contrast significantly decreased.Comparative Example 2 had good contrast but was insufficient to preventthe reflection of the surroundings.

Example 2

An anti-glare layer made of SiO₂ and having a concavo-convexconfiguration was formed, by spraying, on a glass substrate with athickness of 0.7 mm, a surface roughness (Ra) of approximately 0.2 nm,and a coefficient of thermal expansion of 102×10⁻⁷/° C. The averagethickness of the anti-glare layer was approximately 200 nm. The hazevalue of the anti-glare layer was approximately 6.5.

Next, SiO₂ layers and Nb₂O₅ layers were alternately formed, bysputtering, on each of the anti-glare layer and a surface of thesubstrate opposite to the anti-glare layer to give a total of fivelayers on each surface. Thus, an antireflection layer composed ofalternately deposited SiO₂ and Nb₂O₅ layers was provided on theanti-glare layer. In the above manner, an anti-glare/antireflectionmember was produced.

The resultant anti-glare/antireflection member was evaluated in terms ofthe reflection of the surroundings and contrast. The evaluation for thereflection of the surroundings was carried out in the same manner as inExample 1. The evaluation for contrast was carried out in the samemanner as in Example 1, except for placing the anti-glare/antireflectionmember above a liquid crystal screen with a gap of 2.5 mm from thescreen. As a result, also in Example 2, like Example 1, the reflectionof the surroundings was not substantially identified (“⊚”) and the imageon the liquid crystal screen was seen as clearly as when observing itdirectly thereon (“◯”).

The coefficient of thermal expansion of the anti-glare/antireflectionmember is not always equal to that of the liquid crystal screen. If theanti-glare/antireflection member and the liquid crystal screen havingdifferent coefficients of thermal expansion are in close contact witheach other, stress is applied to both the anti-glare/antireflectionmember and the liquid crystal screen when the temperature changes.Therefore, it is preferred in some cases to place theanti-glare/antireflection member and the liquid crystal screen at adistance from each other. However, when a gap is provided between theanti-glare/antireflection member and the liquid crystal screen, thecontrast normally tends to decrease. Unlike this, when as in Example 2an antireflection layer is provided on an anti-glare layer and anotherantireflection layer is provided on the surface of a substrate oppositeto the anti-glare layer, good contrast was achieved even in the presenceof a gap between the anti-glare/antireflection member and the liquidcrystal screen. From the viewpoint of achieving good contrast, it ispreferred to, as in Example 2, provide an antireflection layer on ananti-glare layer and provide another antireflection layer also on thesurface of a substrate opposite to the anti-glare layer.

Example 3

An antifouling layer was provided in the following manner on anantireflection layer of an anti-glare/antireflection member obtained inthe same manner as in Example 1.

A fluorine-based coating agent (OPTOOL DSX (registered trademark)manufactured by Daikin Industries, Ltd.) was applied on theantireflection layer and then dried to form an antifouling layer. Thethickness of the antifouling layer was approximately 20 nm.

The resultant anti-glare/antireflection member includes the anti-glarelayer formed on the substrate, the antireflection layer formed on theanti-glare layer, and the antifouling layer formed on the antireflectionlayer.

The resultant anti-glare/antireflection member was evaluated in terms ofthe reflection of the surroundings and contrast. The evaluation for thereflection of the surroundings was carried out in the same manner as inExample 1. The evaluation for contrast was carried out in the samemanner as in Example 1, except for applying an adhesive layer on thefirst principal surface and gluing the anti-glare/antireflection memberto the liquid crystal screen via the adhesive layer. The adhesive usedwas KE-1051J A/B manufactured by Shin-Etsu Chemical Co., Ltd. and thethickness of the adhesive layer was 5 μm. As a result, also in Example3, like Examples 1 and 2, the reflection of the surroundings was notsubstantially identified (“⊚”) and the image on the liquid crystalscreen was seen as clearly as when observing it directly thereon (“◯”).

In addition, the peel resistance of the antifouling layer was evaluatedin the following manner.

The evaluation for the peel resistance of the antifouling layer wascarried out by placing steel wool #0000 on the antifouling layer, movingthe steel wool back and forth 2000 times at a rate of 40 times perminute with a stroke length of 40 mm under a load of 500 gf/cm², andthen measuring the contact angle between the antifouling layer and waterdroplets. The contact angle was measured in accordance with the ATAN θ/2method based on Young's Equation. Specifically, if the contact angleafter the back-and-forth movement of the steel wool was at the samelevel as that before the placement of the steel wool, this was evaluatedas a “◯”. If the contact angle after the back-and-forth movement of thesteel wool significantly decreased from that before the placement of thesteel wool, this was evaluated as a “X”.

As a result, the contact angle after the back-and-forth movement of thesteel wool was at the same level as that before the placement of thesteel wool (“◯”).

Comparative Example 3

The member of Comparative Example 2 was used instead of theanti-glare/antireflection member of Example 1 and an antifouling layerwas formed on the antireflection layer of the member in the same manneras in Example 3. The resultant member was evaluated in terms of thereflection of the surroundings and contrast in the same manner as inExample 3.

As a result, like Comparative Example 2, Comparative Example 3 had goodcontrast (“⊚”) but was insufficient to prevent the reflection of thesurroundings (“Δ”).

In addition, the peel resistance of the antifouling layer was evaluatedin the same manner as in Example 3. As a result, the contact angle afterthe back-and-forth movement of the steel wool significantly decreasedfrom that before the placement of the steel wool (“X”).

Example 4

An anti-glare layer made of SiO₂ and having a concavo-convexconfiguration was formed, by spraying, on a substrate of alkali glassOA-10G manufactured by Nippon Electric Glass Co., Ltd. with a thicknessof 0.1 mm and a surface roughness (Ra) of approximately 0.2 nm. Theaverage thickness of the anti-glare layer was approximately 60 nm. Thehaze value of the anti-glare layer was approximately 3.

Next, an antireflection layer was provided on the anti-glare layer inthe same manner as in Example 1.

Furthermore, an antifouling layer was formed on the antireflection layerin the same manner as in Example 3.

The resultant anti-glare/antireflection member was evaluated in terms ofthe reflection of the surroundings and contrast. The evaluation for thereflection of the surroundings was carried out in the same manner as inExample 1. The evaluation for contrast was carried out in the samemanner as in Example 1, except for providing a pressure-sensitiveadhesive layer on the first principal surface of theanti-glare/antireflection member and pressure-sensitively attaching theanti-glare/antireflection member to a touch panel-equipped display viathe pressure-sensitive adhesive layer. The pressure-sensitive adhesiveused was PD-S1 manufactured by PANAC Co., Ltd. and the thickness of thepressure-sensitive adhesive layer was 25 μm. As a result, the reflectionof the surroundings was identified a little (“◯”). In terms of contrast,the image was seen more clearly than when observing it directly on thetouch panel-equipped display (“⊚”).

In addition, the peel resistance of the antifouling layer was evaluatedin the same manner as in Example 3. As a result, the contact angle afterthe back-and-forth movement of the steel wool was at the same level asthat before the placement of the steel wool (“◯”).

REFERENCE SIGNS LIST

-   -   1 . . . anti-glare/antireflection member    -   10 . . . base material    -   10 a . . . anti-glare layer    -   11 . . . base material body    -   11 a . . . first principal surface    -   11 b . . . second principal surface    -   12 . . . island layer    -   20 . . . antireflection layer    -   30 . . . antifouling layer

1. An anti-glare/antireflection member comprising: a base materialprovided in a surface layer thereof with an anti-glare layer having aconcavo-convex configuration; and an antireflection layer provided onthe anti-glare layer.
 2. The anti-glare/antireflection member accordingto claim 1, wherein the base material comprises: a base material body;and an island layer disposed on the base material body and forming theanti-glare layer.
 3. The anti-glare/antireflection member according toclaim 2, wherein the base material body is formed of a resin film, aglass film, a resin plate or a glass plate.
 4. Theanti-glare/antireflection member according to claim 1, furthercomprising, on a surface of the base material opposite to theantireflection layer, another antireflection layer.
 5. Theanti-glare/antireflection member according to claim 1, wherein theantireflection layer is formed of a low-refractive index layer having alower refractive index than the base material.
 6. Theanti-glare/antireflection member according to claim 1, wherein theantireflection layer is formed of a structure in which low-refractiveindex layers having a relatively low refractive index andhigh-refractive index layers having a relatively high refractive indexare alternately deposited.
 7. The anti-glare/antireflection memberaccording to claim 1, further comprising an antifouling layer containingfluorine and provided on the antireflection layer.
 8. A method forproducing the anti-glare/antireflection member according to claim 1,wherein a light-transmissive material is applied on a surface of alight-transmissive plate by spraying to form an island layer thereon,thus preparing the base material composed of the light-transmissiveplate and the island layer.
 9. A method for producing theanti-glare/antireflection member according to claim 1, wherein a surfaceof a light-transmissive plate is blasted to form the concavo-convexconfiguration, thus preparing the base material.
 10. The method forproducing the anti-glare/antireflection member according to claim 9,wherein the surface of the light-transmissive plate is etched afterbeing blasted.